HERMOSILLO, Mexico (CNN) -- President Felipe Calderon traveled to Hermosillo on Saturday to meet with health officials as the death toll of a day care center fire there grew to 38 children.

A crib and baby seats lie outside a day care center Friday in Hermosillo, Mexico, as police cordon off the area.

The cause of Friday's blaze remained unknown, but investigators concluded that the fire did not start inside the ABC Day Care, Eduardo Bours, the governor of Sonora state said.

As of Saturday night, 23 children remained hospitalized, 15 of them in critical condition, Sonora spokesman Daniel Duran told CNN. Another 10 children had been transported to other hospitals: eight to Guadalajara, one to Ciudad Obregon, and one to Sacramento, California.

A team of 29 medical experts in Hermosillo were deciding if any more victims would be moved to the Shriners Hospital in Sacramento, or elsewhere.

In addition, six adults were injured, Duran said.

"Without a doubt this is the worst disaster we've had," Bours told CNN.

The president arrived with Interior Secretary Fernando Gomez Mont and Health Secretary Jose Angel Cordova to get firsthand updates from doctors and investigators, the state news agency Notimex reported.

Calderon ordered the nation's attorney general to investigate the blaze.

Most of the victims died from smoke inhalation and not burns, Bours said. But the fire was enough for the roof to collapse, he added.

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At the time of the blaze, 142 children were inside the ABC Day Care. The day care is for children ages 2 to 4, but Bours confirmed that children even younger were among the victims.

All the children at the day care had been accounted for by Saturday evening, Bours said.

A severely burned 3-year-old girl arrived Saturday at the Sacramento hospital -- where pediatric burn treatment is a specialty -- and was in critical condition, according to Dr. Tina Palmieri, assistant chief of the burn unit.

The child was burned over 80 percent of her body, the doctor told reporters. She said the hospital normally can save just over half of the children with burns that severe.

In Hermosillo, a large crowd gathered outside of the emergency entrance of the city's general hospital and many people consoled each other, video from the scene showed.

"They told me that this happened in a matter of five minutes," Hermosillo Mayor Ernesto Gandara told reporters after surveying the scene.